Magnetic Field Sensor Using a Physical Model to Pre-Calculate the Magnetic Field and to Remove Systematic Error due to Physical Parameters

Speed and angle measurements of rotating shafts are very important in automotive applications. Typical sensing arrangements for angular measurements using the magnetic principle are analyzed in this paper. It is shown that such sensor arrangements are prone to phase errors. The phase error mainly depends on the distance between sensor element and rotating shaft. By employing finite element simulations, a variety of frequently used magnetic field sensor configurations are investigated. Measurements complement the simulations and confirm correct simulation results. Due to mounting tolerances and mechanical vibrations in automotive applications the sensor distance is varying and dynamic phase errors appear. The accuracy of measurement can only be improved if these errors get compensated. This can be done with the help of digital signal processing.